Drop in gas mileage per gallon (from 30 to 22)

Tiny
THECHUCKER
  • MEMBER
  • 2012 TOYOTA CAMRY
  • 2.5L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 66,000 MILES
Dealership claims that when a new battery was installed (not by them), the computer was not set correctly. The dealership disconnected the battery, reconnected it, and reset the computer. However, they told us that the gas mileage would improve slowly over time - and that we would see slow incremental improvement. Does this make sense? Is this possible? (Because of something that the car model has called "eco-boost")
Sunday, December 6th, 2015 AT 4:45 AM

17 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
It is possible. The computer has adaptive capabilities. It will slowly adapt the fuel mixture to your driving style and any other things effecting engine operation.
Was this
answer
helpful?
Yes
No
Sunday, December 6th, 2015 AT 6:16 AM
Tiny
PATCHERI
  • MEMBER
  • 1 POST
  • 2005 TOYOTA CAMRY
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 62,000 MILES
My gas milage has dropped in the past few tanks. I have always monitored my milage; so a 5-10% drop is noticable. It has been colder for past month, but I don't drive that much in a warm up mode. Seems like I smell more fuel in exhaust than I remember. Anything I can check? I also noticed Toyota suggests a valve adjustment at 60k miles; and wonder if this is related.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:51 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Hi there,

Incorrect valve clearances can affect economy, also have the tune items sen to and get a scan done to check for any unresolved fault codes, start here.

Mark (mhpautos)
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:51 PM (Merged)
Tiny
TORRES.CHRISTIAN23
  • MEMBER
  • 1 POST
  • 2001 TOYOTA CAMRY
  • 266,000 MILES
My exhaust pipe and mufflier are no good. If I get it fixed would if improve my mpg? If so would if be alot or alittle bit
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:51 PM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 34,330 POSTS
"No good" doesn't say anything. What is wrong with these parts? If the muffler is rusted out already a baffle could be collapsed and blocking exhaust gas flow. That can make the engine work harder to push the exhaust out. If something was crushed, that will also restrict flow.

A leak before the front oxygen sensor can allow outside air to be drawn in between the pulses of exhaust flow. The oxygen in that air can be detected by the oxygen sensor as a lean condition. The Engine Computer will respond by commanding more fuel to enter the engine.

Both of those conditions are not real common, and it's impossible to say what the impact on fuel mileage would be without knowing more details.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:51 PM (Merged)
Tiny
IK
  • MEMBER
  • 6 POSTS
  • 1998 TOYOTA CAMRY
  • 2.0L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 230,000 MILES
When to use overdrive, is it in the city(we move and stop a lot in my city) or when I'm travelling on the highway.
My question is relation to fuel economy and my transmission. Want to use less fuel and don't want my transmission to go bad.
Thanks.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
You can use overdrive at any time if you are at repeated stop and go then go to drive but even on city eway it will do better.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
IK
  • MEMBER
  • 6 POSTS
Pardon me bro. Still not clear. Wish you would give me definites.
Use overdrive or not in city where you usually have stop and go situations.
Use overdrive or not on highway.
Question is in relation to the fuel and transmission safety.
Thanks.
:)
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Use overdrive on the expressway and in city as long as it's not stop and go when it does that then switch to drive. In either case you won't hurt the transmission. The thing that kills a transmission is overheating it like towing a heavy load which your car can't tow that heavy of a load. Fuel mileage is up and down because of the way people drive their cars as well as engine problems like check engine light coming on and not fixing the problem.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
IK
  • MEMBER
  • 6 POSTS
Cool. Ok then. Since my town is a go and stop kinda place(you stop, move for about 2-3 mins then there is another reason to stop again, then you move for say 5 mins without stopping and then stop again), I will stick to leaving it off(from what you said) then at the end of the month when I always travel, will switch to overdrive for the highway trip, put it off again when I get to my destination to put it on on my trip back to base.
Is this right/ok, @Hmac300.
My fuel consumption will be more economical and I won't fry my transmission.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Yup
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
IK
  • MEMBER
  • 6 POSTS
Thanks Sir. Will run this for a while, will give you a feedback in a while.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
IK
  • MEMBER
  • 6 POSTS
Good day Hmac Sir. Trust alls good with you. Been running the car just the way agreed, overdrive off in the city, overdrive on when on the highway, and boy, with the overdrive off in the city, the fuel in the car kinda just disappears, jeez, its all gone before you know it, on the highway with the overdrive on, its bettter.
What you think man?
Rem, its a toyota camry 1998 auto.4 cyl. Done 230k on the odo.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
I kinda said in one of my replies it really doesn't matter a heck of a lot but to keep it in overdrive all the time. Sometimes you just have to let people learn by themselves. Keep it in overdrive.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
IK
  • MEMBER
  • 6 POSTS
Thanks man. It stays on overdrive now. Thanks again.
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
WONGLEETOY
  • MEMBER
  • 1 POST
  • 1995 TOYOTA CAMRY
I have a 1995 Camry LE 4 with 112K miles on it. It has always run well but the last few months I noticed a major decrease in mileage per gallon 17 mpg. I changed the most common items: Spark Plugs (looked ok), wires, cap and rotor. Added fuel cleaner still no change. Car runs great but has poor mileage.

Also is there a true code reader for a 1995 Camry? Seems that some company advertise that it is covered but in reading the find print, it is not.

Please advise.

Mitch
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
What about fuel filter/air cleaner/PCV valve these things are tune-up items.

I'll bet the oxygen sensor is 12yrs old and has never been changed.

When this sensor starts getting lazy it would confuse the computer is to how to adjust fuel
Was this
answer
helpful?
Yes
No
Tuesday, January 7th, 2020 AT 12:52 PM (Merged)

Please login or register to post a reply.

Related Engine Poor Mileage Content

VIEW MORE